His book and blog focus primarily on the benefits of evolutionary fitness and nutrition – the concept that, from an evolutionary and biological standpoint, high-carb diets eaten around the world today are not suitable for optimal human nutrition. Rather, we should revert to a simpler, more “primal” approach to diet and exercise: Eat mostly animals and plants, lift heavy stuff and move around (frequently and slowly, with an occasional sprint) like our ancestors did. According to Sisson, low carb is the way to go; we’ve been poisoned by modern food – including not just processed snacks and fast food, but also grains, sugars and chemically-altered fats.

I’ve come to really enjoy Sisson’s site, and I subscribe to a lot of what he's said about nutrition in “The Primal Blueprint.” (It’s also great that he’s a fellow barefoot running and Vibram FiveFingers enthusiast.) Especially in my first month of P90X, a super-low-carb diet was the catalyst for a significant change in my body composition. I’m a firm believer in eating whole, unprocessed foods whenever possible, and I’m perfectly happy eating salads (with some protein: meat, nuts, beans, etc.) for breakfast, lunch and dinner.

The bottom line is this: grains = carbs. Unnecessary at best, but flat out unhealthy at worst, they’re not the wholesome staples they’re made out to be. Talk about double taxation: Our bodies pay for what our trusty government subsidizes Big Agra for. The best – really the only way – to achieve a low carb, whole foods diet is to ditch the grains. (Your body will be better off without inflammation, the insulin roller coaster, not to mention the constant onslaught of creepy gluten and lectins.) A diet very low or entirely without grains (low-carb) has been shown to decrease risk for problems associated with diabetes, to lower blood pressure, alleviate heartburn symptoms, and shed abdominal fat. Finally, low carb diets have been associated with significant “reductions in a number of pro-inflammatory cytokines, chemokines, and adhesion molecules.”

One of the selling points of “The Primal Blueprint” is that it encourages you to simplify – to stop worrying about calorie counting or tightly-scripted exercise routines. But by effectively banning grains outright, Sisson actually makes it a lot harder to stick to the “Primal Eating Plan.” It hurts my head to think of the planning and forethought required to come up with a substitute for our pizza-loving kids, or the pain of having to scoop out the insides of a burrito to avoid eating a whole wheat tortilla.

I’m no expert, so I can’t speak to whether Sisson’s vehement arguments against grains are scientifically valid or not. But regardless, I don’t think that I can – or want to – eliminate grains altogether from my diet. It's just not realistic. I’ve already drastically limited my consumption of carbs over the past half-year; cutting added sugar almost entirely out of my diet and loading up on bananas and whole grains only after a hard morning workout. Grains help keep me from bonking when I push myself hard while working out. And besides, they fucking taste good.

“The Primal Blueprint” suggests that even those carbs that are ingested immediately after a workout should be avoided. But didn’t Mark Sisson create and help market the P90X Recovery Drink, which happens to be loaded with carbs?

Sisson’s response is a bit surprising – particularly because he now appears to be disavowing his own creation, and distancing himself from the claims he made in Beachbody's advertisements:

I did design the P90X post-workout shake. My main “business” is actually designing supplements, which I have done for several companies including my own. In the case of the P90X shake, I was contacted to design a product line to meet their particular demographic and price specs. At the time of design, the main challenge was to refill muscle glycogen immediately after a relatively longer and harder workout such that you could be ready to go again the very next day, so the main exercise premise deviated from PB [The Primal Blueprint]. Also, the diet being espoused by P90 staff dietitians was a higher carb diet, so I had to create something that would give the carb-burners a continuous source of muscle glycogen.

The prevailing technology at the time was to combine 80% carb and 20% protein, which I did using mainly fructose. I added antioxidants and creatine along with a few other recovery assists and made it the best tasting drink on the market. I appeared in their advertising at first as part of the deal, but I am no longer affiliated with the P90X program. Apparently, my interviews are still being used by P90 and there’s nothing I can do about that. Obviously, technology has changed in the years since that product was designed and I personally don’t follow a [post-workout] carb-loading strategy.